Flexible bags when made by automated equipment are generally formed either by transverse seals on tubular plastic film, by marginally sealing two separate layers of film, or by folding a single ply and sealing the two plies thus formed at margins to generate a closed bag.
In the manufacture of some plastic bags, for example those for containing parenteral solutions, blood or blood plasma, access ports are provided. Furthermore, with bags which are to be used for collecting and storing such products, the interior surfaces should be clean and free of particulate matter so as to avoid clogging of needles or avoid the infusion of particulates into patients receiving these products. To provide ports and to assure freedom of particulates, such requirements have imposed problems in attempts to automate manufacturing processes. In current practice, some of the steps in a process are automated and some are performed by assembly line personnel. For example, sheets of plastic film, to which ports have been sealed along a center line of the sheet, are manually folded at the center line, the two plies then positioned on a sealing die, and any wrinkles smoothed out by hand before edge seals are effected by the sealing die. Regardless of how much care is taken, the fact remains that manual operations by line personnel contribute significantly to the generation of particulate matter and make it extremely difficult if not impossible to manufacture bags free of particulates.
Automation in the manufacture of ported bags, although most desirable from the standpoint of helping to eliminate many of the contamination problems associated with manual operations, as well as to increase the speed and efficiency in the fabrication of bags, nevertheless poses a number of technical problems, particularly when dealing with flexible plastic film. A continuous sheet of such film is difficult to maintain in a straight line and in uniform longitudinal dimensions as it is made to progress through various processing stages in the fabrication of bags. In folding plastic sheet over to form two plies to be sealed at fixed areas to form bags, the nature of the plastic generally causes wrinkles to be formed which must be removed prior to sealing. These and other characteristics inherent in flexible plastic film add to the difficulties in trying to completely automate the fabrication of ported plastic bags.